Electroplating barrel

ABSTRACT

AN ELECTROPLATING BARREL ADAPTED FOR MOUNTING ROTATABLY WITHIN A TANK OF A PLATING SOLUTIONS, SAID BARREL COMPRISING SIDE PANELS AND END WALLS DEFINING A CHAMBER WITHIN WHICH BULK QUANTITIES OF SMALL WORKPIECES MAY BE ELECTROPLATED, THE PANELS BEING FORMED WITH SLOTS THERETHROUGH OF GREATER WIDTH AT THE OUTER SURFACE OF THE WALL OF THE BARREL THAN AT THE INNER SURFACE OF SAID WALL, WHEREBY UPON ROTATION OF THE BARREL A CONCENTRATED PLATING SOLUTION IN THE TANK IS ADAPTED TO FREELY ENTER WITHIN THE BARREL TO MAINTAIN THEREIN A DESIRED DENSITY OF THE PLATING SOLUTION TO COMPENSATE FOR AND REPLACE THE METAL DEPOSITED ON THE WORKPIECES FROM SAID SOLUTION.   D R A W I N G

June 1, 1971 c. R. CAMPANA 3,582,526

ELECTROPLATING BARREL Filed Dec. 15, 1967 INVENTOR. CHARL E5 A? CAM/mmATTOPA/EF United States Patent US. Cl. 204-213 6 Claims ABSTRACT OF THEDISCLOSURE An electroplating barrel adapted for mounting rotatablywithin a tank of a plating solution, said barrel comprising side panelsand end walls defining a chamber within which bulk quantities of smallworkpieces may be electroplated, the panels being formed with slotstherethrough of greater width at the outer surface of the wall of thebarrel than at the inner surface of said wall, whereby upon rotation ofthe barrel a concentrated plating solution in the tank is adapted tofreely enter within the barrel to maintain therein a desired density ofthe plating solution to compensate for and replace the metal depositedon the workpieces from said solution.

The present invention relates to an electroplating barrel and aims toprovide certain improvements therein.

Electroplating barrels as heretofore proposed and currently in usedepend upon a multiplicity of perforations in the wall of the barrel orin panels constituting such wall for the flow of current and circulationof the plating solution from the tank into the barrel. Where suchperforations are relatively large to permit free circulation of theplating solution, small workpieces to be plated in the barrel may fallthrough such perforations. Where the perforations are made of smalldiameter, the flow of current and the circulation of solution from thetank into the barrel are restricted. Also if the perforations are madeof large diameter, the wall of the barrel or of the panels must be maderelatively thick to sustain the weight of the workpieces to be platedand as a concomitant of such greater thickness, the length of theperforations is increased, thereby impeding the passage of current andthe circulation of plating solution, thus decreasing the efficiency ofthe plating operation.

The primary object of the present invention is to provide a novelelectroplating barrel which overcomes the deficiencies of the prior artconstructions having perforated barrel walls.

A further object of the invention is to provide an improvedelectroplating barrel which eliminates the provision of perforations inthe wall thereof and the concomitant limitations resulting from suchperforations.

A still further object of the invention is to provide an electroplatingbarrel which is exceedingly simple in construction and of highefficiency in operation.

The foregoing and other objects of the invention, not hereinbeforespecifically enumerated I accomplish by providing an electroplatingbarrel comprising a plurality of side panels and two end walls defininga chamber, the panels being of unique form in that they aresubstantially flat and have slots therethrough which are of greaterwidth at the outer surface of the wall of the barrel than at the innersurface of said wall. Preferably the slots are of substantially V-shapeor Y-shape in transverse section.

The invention will be better understood from the detailed descriptionwhich follows when considered in connection with the accompanyingdrawing wherein:

FIG. 1 is a perspective view of a plating barrel embodying my invention,the barrel being shown in its environmental setting;

Patented June 1, 1971 "ice FIG. 2 is a transverse sectional view of theplating barrel taken along the plane of the line 22 of FIG. 1;

FIG. 3 is a perspective view of a panel element constituting a portionof the wall of the plating barrel;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3.

Referring first to FIG. 1 of the drawing there is shown a typicalenvironmental arrangement of a plating barrel and the mounting thereofin use currently in the electroplating industry. The principal parts ofsuch typical arrangement consist of a framework 10 which has a pair ofdepending legs 12 which rotatably supports an electroplating barrel 14adapted to be driven by an electric motor 16 through a gear train 18,20, 22. As is conven tional, the barrel is a polygonal container, hereinshown as hexagonal, formed of end walls 24 and 26, a plurality of rails28 and panels 30 suitably held in said rails between said end walls. Thegear 22 is fixedly connected to the end wall 24 and through a centralopening in the gear 22 and in the end wall 24 and from the end wall 26extend a pair of flexible danglers or cathode members 32 of a length tonormally make contact with the workpieces in the barrel as the latter isrotated. To lower the barrel into and raise it from a tank containing aplating solution, the framework 10 is provided with a cross beam 34 towhich is affixed a ring 36 for engagement by a suitable hoist.Electrical connections (not shown) are made with the motor 16, thecathodes 32 and the anodes to complete the electrical circuit forcarrying out the plating operation as the workpieces are tumbled as thebarrel 14 is rotated. As thus far described the construction andarrangement of parts maye be considered as conventional and per se arenot part of my invention.

The novelty of the present invention resides in the unique constructionof the plating barrel 14 wherein the panels 30 are rectangularsubstantially flat members formed of suitable synthetic material, suchas polypropylene, methylmethacrylate and the like, which is notelectrically conductive nor adversely affected by the plating solution.The panels are slidably mounted in mortise grooves 29 in the rails 28and are held in said grooves by the end walls 24, 26 in a conventionalmanner. The panels are formed with slots 38 therethrough which are ofgreater width at the outer surface of the wall of the barrel than at theinner surface of said wall. Preferably the slots extend transversely tothe axis of the barrel and at the outer surface of the wall of thebarrel, for at least a portion of their depth, are substantially V-shapein transverse section with the sides of the V directed inwardly towardeach other from said outer wall surface. As shown in the drawing theseslots are Y-shape in transverse section which as will be obvious have aV-portion 40 and a stern portion 41. Preferably the dimensions of theslots at the V-portion thereof at the outer surface of the barrel Wallare between three and six times as wide as at the inner surface of saidwall. Where the slots are of Y-shape, the V-portion of the slots at theoutersurface of the wall of the barrel are between three and six timesas wide as the stem portion of the slots with the V-portion and stemportion of approximately the same depth.

For gaining access to the interior of the barrel to charge and removethe workpieces therefrom, one of the panels 30 is formed as a door 3011which may be positioned and withdrawn radially from the barrel. Toaccomplish this the grooves or rabbets 28b in the rails 28a whichaccommodate the door are slightly different from the grooves 29 in thatone of the grooves is a right angular rabbet groove. The door 30a isformed with a central outward projecting handle 42 which serves tomanually insert and remove the door and also with spacing blocks 43 forengagement by spring clips 44 to hold the door in locked position.

It is also preferable that the panels, other than the door panel, bemade as sub-panels 31 of rectangular form mounted in end-to-end abuttingrelation in the grooved rails 28 to permit easy change-over of suchsub-panels to accommodate different size workpieces in the barrel or forreplacement of any individual sub-panel in the event of wear or damagethereto from any cause.

The advantages accruing from the present invention because of the largeopen areas in the panels provided by the slots, as opposed toconventional perforations, is that more highly concentrated solutionfrom the tank is able to freely enter the barrel and carry with it themetal in solution to provide a desired density of the plating solutionwithin the barrel for better electrodeposition of metal on theworkpieces. Faster and more uniform deposition of metal is assured sincehigh voltages can be used because of the rapid solution exchange rateand the exposure of the work load to the unimpeded current flow whichresults from the open slots. Production runs with the barrel of thepresent invention on a comparative basis with conventional perforatedbarrels have shown an increase in the deposition rate up to 300%Although I have shown and described a preferred embodiment of myinvention, it is to be understood that details of the panel constructionmay be varied within the range of mechanical and engineering skillwithout departing from the spirit of the invention as hereinafterclaimed.

What I claim is:

1. An electroplating barrel in the form of a polygonal container,comprising a pair of end walls, grooved retainers connecting said wallsand flat panel elements of less length than the retainers slidablymounted in end-toend abutting relation in said grooved retainers anddefining a chamber within which bulk quantities of small workpieces maybe electroplated, each panel element having an array of parallel slotsextending substantially across one dimension thereof, said slots beingof greater width at the outer surface of each panel than at the innersurface thereof.

2. An electroplating barrel according to claim 1, wherein the slots inthe panels at the outer surface of the wall of the barrel for at least aportion of their depth are substantially V-shape in transverse sectionwith the sides of the Vs directed inwardly toward each other from saidouter wall surface.

3. An electroplating barrel according to claim 2, wherein the slots aresubstantially Y-shape in transverse section.

4. An electroplating barrel according to claim 2, where: in theV-portion of the slots at the outer surface of the barrel wall arebetween three and six times as wide as at the inner surface of saidwall.

.5. An electroplating barrel according to claim 3, wherein theV-portions of the Y-slots at the outer surface of the wall of the barrelare between three and six times as wide as the stem portion of theY-slots.

6. An electroplating barrel according to claim 5, wherein the V-portionof the slots and the stem portion thereof are of approximately the samedepth.

References Cited UNITED STATES PATENTS 449,890 4/1891 Zingsem 204-2132,243,728 5/1941 Davis 204-213 3,153,624 10/1964 Jackson 204-213 FOREIGNPATENTS 813,915 9/1951 Germany 204-213 841,711 7/1960 Great Britain204-213 1,272,165 1961 France.

1,485,172 1967 France.

882,937 1953 Germany. 1,119,623 1961 Germany.

JOHN H. MACK, Primary Examiner T. TUFARIELLO, Assistant Examiner US. Cl.X.R. 259-89

